Please note that the copyright for this course project is retained by the instructor.

Goal

To integrate anatomy, neurology, radiology, clinical history-taking and problem solving, principles of occupational health and illness/injury epidemiology in a teaching exercise tailored to first-year medical students at mid-year.

Objectives

1. To reinforce principles of good history-taking, interviewing, and differential diagnosis-formulating skills in problem-solving.
2. To reinforce the methods of formulation and analysis of a differential diagnosis.
3. To learn how the anatomy of peripheral nerves in the upper extremity relates to specific clinical syndromes and application of this knowledge in evaluation of a differential diagnosis.
4. To teach students about the role of workplace and other exposures in causing and exacerbating common medical conditions, and how this perspective leads to effective treatment and prevention strategies.

Overview

Students get a very brief introduction to the case one morning before Anatomy class begins, then go to the lab. There are 4 students per cadaver, so if we have 4 differential diagnoses, each student at a cadaver is assigned one possibility for the case. We give each student a brief description of the case, as well as some focused readings on their differential possibility (one of the four listed in the full text below). They spend the next 2 weeks dissecting the upper extremity, and think about how their diagnosis is related to the anatomy they see before them.

On 12/3, we begin with an overview of upper extremity neuroanatomy, and then review the (limited) information we've told them about the case. We then review the basics of each differential diagnosis -- typical history, symptoms, signs, features of the case that argue for or against this diagnosis, and further information needed to confirm the diagnosis. Of course, we have the students supply the information to us. Finally, they interview a real-live Carpal Tunnel Syndrome (CTS) patient, drawn from one of our hand surgeon's clientele. We show them how a good physical examination can establish the diagnosis in most cases. We close with a discussion of the causes and occurrence of CTS, and the issues that arise when it is related to work -- emphasizing the MD's role in prevention.

Schedule for 12/3:

9:30 - 10:15: David Giansiracusa, Anatomy and Pathology of the Hand

10:30 - 11: Review of the differential diagnoses - which is more likely? (Glenn: Pransky and Jane Sargent, Dept. Of Neurology)

11 - 11:15: Differential Neurologic Diagnosis in the upper extremity - keys to remembering what is important (Jane Sargent)

11:15 - 11:45: Interview and examine a patient with the disorder

11:45 - 12:30: Wrap-up: treatment and prevention (Glenn)

MY HANDS HURT (Student handout)

HISTORY
A 38-year-old white female presents with complaints of pain in her right hand. She describes her pain as burning and sometimes tingling, mostly in the hand, but occasionally up the forearm. This occurs at times during the day, can last up to several hours, and also can occur at night, sometimes awakening her from sleep. The pain is mostly unrelated to specific physical activities, but symptoms seem to appear more often when she is driving, reading the paper, and perhaps when her neck is in one position, such as looking up at a movie theater for a prolonged period of time. She sometimes feels better if she moves her neck around or rubs it, or shakes her hand. She says that this has been gradually getting worse over the past 6 months. She hasn't noticed any discoloration, but has noted a little bit of swelling around the right wrist.

Past medical history doesn't reveal any significant medical problems, although she did have a bout of joint pains when she was a child, and was in an auto accident 2 years ago - she was hit from behind. Although she had a lot of soreness immediately after the accident, she said that cleared up fairly well. She is gravida 11, II 11.

Family history - 2 brothers alive and well, without any obvious medical problems; her father died of myocardial infarction at age 72, and her mother died of cancer of the cervix at age 79.

Social history - She is married, and has 2 children ages 12 and 14. She works for a confectionary company.

Review of Systems is positive only for occasional headaches, somewhat irregular but normal menses, an occasional but minor pain in knees and ankles.

PHYSICAL EXAMINATION
Head, eyes, ears, nose, and throat unremarkable. The neck demonstrates full range of motion, but Spurling's maneuver increases a feeling of tingling in the back of the hand. Shoulders - normal range of motion, slight tenderness over the biceps tendon bilaterally. Elbows - normal range of motion, no swelling or focal tenderness. Bilateral forearm examination shows slight puffiness distally on the right compared with the left, with a little bit of pain to palpation. A detailed hand examination shows no swelling of the joints, with full, painless range of motion about the fingers, although there appears to be some tenderness on forced wrist flexion, more so on the right than the left - but no swelling or erythema. Joints appear to be normal.

Cardiopulmonary and abdominal examination are negative. Examination of joints in lower extremities is entirely normal. Neurologic examination - cranial nerves intact and symmetrical. Strength appears normal in flexors and extensors of shoulder, elbow, pronation and supination at elbow, wrist flexors and extensors, deep finger flexors and extensors, and superficial flexors of fingers. Thumb adduction, opposition, abduction and extension strength is normal, and symmetrical in both hands. Sensation - decreased sensation to light touch over the palmar side of the tips of the second and third finger, otherwise normal on the right; entirely normal on the left. Deep tendon reflexes 2+ and symmetrical bilaterally.

Each student will receive 1 of 4 possible diagnoses for this case, described in a short hand-out. Please read the handout, review the relevant Netter and Moore text sections, and think about the possible etiologies of this problem as you begin your dissection over the next 2 weeks. We'd like to think about the anatomy, pathogenesis, diagnosis, presentation, treatment, prognosis, and prevention of this condition; features of the case that do or do not suggest a particular diagnosis.

You will be asked to discuss this in class on 12/3, when we will have the patient come in for you to examine and diagnose. See you then! - Glenn Pransky, John Cooke, and Jane Sargent.

CERVICAL RADICULOPATHY

This condition is caused by pressure or damage to nerve roots exiting the cervical spinal column, usually from a cervical disc, or from osteophytes that have narrowed the intervertebral foramen. This foramen is the space between the pedicles of two adjacent cervical vertebrae, where the spinal nerve exits the spinal column. The most common nerve roots affected are the C6 and C7 nerve roots, although C5 and C8 can also be affected.

There may be a history of sudden neck pain or a 'pop' in the neck while lifting, or recent exertion or trauma. Often, there is a history of intermittent neck pain, which becomes more severe, with pain radiating into the neck, scapula, and down the arm. However, some patients first notice symptoms in a cervical nerve root distribution in the arm or hand.

....
Pain is often better when lying down and exacerbated by doing activities which involve turning the head towards the affected side. Patients frequently hold their head slightly leaning forward, limiting rotation towards the affected side. Physical exam shows decreased neck extension, decreased lateral rotation and flexion towards the affected side. The Spurling maneuver, which involves extending the neck, rotating the head towards the affected side, and the examiner pushing down gently on top of the head, reproduces arm symptoms through compression of affected nerve roots. Bilateral symptoms or bladder problems often indicate a spinal cord problem; lower extremities should always be examined.

Treatment begins with soft collar neck immobilization. Patients should avoid carrying heavy objects on the affected side. If the radiculopathy is severe depending on clinical course surgery may be needed, but half of patients spontaneously improve.

(Netter's Atlas plates p454, 455)

CARPAL TUNNEL SYNDROME

Carpal Tunnel Syndrome is cause by compression of the median nerve at the wrist, in the carpal tunnel. This is a very frequent condition, and will affect approximately 5% of the population at some point in their lives, and is mostly seen in persons between 40 and 60 years old. Factors that predispose to developing this problem include diabetes, hypothyroidism, wrist fracture, sudden weight gain, menopause, pregnancy, and repetitive, forceful activities involving the hands.

Symptoms often begin with numbness and tingling in the first three fingers, which is worse at night, often awakening patients. There are often symptoms radiating up the forearm, and sensitivity to pressure or tapping over the volar wrist. Symptoms are often exacerbated by holding the hands in an elevated position (when reading a paper or driving) and are relieved by shaking the hands.

Pathophysiology - look at the diagram of the carpal tunnel; you will see that the carpal tunnel is bounded by bone on three sides with a stiff ligament (the carpal ligament) across the top, and thus if there is any swelling of the tendons that traverse the carpal tunnel (deep and superficial flexor tendons of the fingers), or change in the tunnel itself this will result in pressure on the median nerve. Elevated intracarpal pressure results in degeneration through an ischemic process. Nerves that are unhealthy for other reasons (diabetes, alcoholism) are more susceptible to compression.

Diagnosis is established by obtaining a history of numbness and tingling in the palmar fingers sometimes exacerbated by specific activities, generally worse at night. Patients often say that all fingers go numb. Physical examination rules out cervical nerve root, brachial plexus, or forearm nerve entrapment. The Tinel's test, which consists of tapping over the median nerve just proximal to the carpal tunnel, results in an "electric shock" feeling radiating proximally or distally, and is positive in over 60% of cases, but is also positive in at least 5% of normal individuals. The Phalen's test, prolonged forced flexion of the wrists, usually results in numbness/tingling in a median nerve distribution. These symptoms occur on the palmar aspect of the first three and a half fingers; sometimes, only the first, second, or third finger develop numbness with this maneuver. As this syndrome progresses, the motor component of the median nerve is sufficiently affected to cause weakness and wasting of the abductor pollicis brevis and opponens

Early cases can often be successfully treated by conservative treatment, as well as cessation of the aggravating activities, and correcting underlying medical causes. Often, a wrist splint at night is useful, to hold the wrist in a neutral position. Corticosteroid injections into the carpal tunnel can reduce swelling and provide relief, which is only temporary if underlying causes cannot be corrected. Carpal tunnel surgery involves releasing the carpal ligament through a palmar or endoscopic approach, and usually results in relief of carpal tunnel symptoms. However, hand pain may persist if there are other problems (such as tendinitis), or if the compression was severe.

(See Moore p603,605)

MEDIAN NERVE LESIONS OTHER THAN CARPAL TUNNEL SYNDROME

Several syndromes can lead to median nerve compression, and associated weakness and numbness in the hand. Although the carpal tunnel syndrome is the most common one, others include forearm fractures, tumors, infection and compartment syndromes, and the pronator syndrome.

The pronator syndrome is compression of the median nerve as it enters the forearm, just proximal to the anterior interosseous branch. Usually, the median nerve becomes entrapped below the fibrous band at the distal portion of the biceps, the lacertus fibrosus. Occasionally, entrapment can also occur between the two heads of the pronator teres. Patients have often been involved in activities with forced pronation of the hand, either at work or in avocational activities at home.

Symptoms usually include pain in the volar forearm, increased by use and relieved by rest, with more pain in the forearm than in the hand, although the sensory symptoms may be identical to those of the carpal tunnel syndrome, with additional complaints of numbness in the palm.

Physical examination shows pain on local palpation in the upper forearm and a positive Tinel's test - tapping over the area of entrapment results in pain and an "electric shock" feeling radiating distally, often into the hand. Resisted active pronation from a fully-supined position reproduces symptoms in the pronator syndrome, when the impingement of the median nerve is in the region of the pronator teres. There is usually weakness of the flexor pollicus longus.

Treatment is specific to the cause; in the pronator syndrome, avoiding the causative activity and rest. Surgery may be required to release the entrapment.

(See Pronator Syndrome, p576 Moore text)

PANCOAST TUMOR

The apex of the lung lies just above the first rib, and thus is quite close to the brachial plexus. Tumors involving this region can spread to the supraclavicular area, and involve the lower portion of the brachial plexus. Although symptoms in the shoulder and neck are variable, these patients have pain in the forearm and hand which may be severe, as well as sensory loss and weakness that is usually concentrated in the region of the ulnar nerve. There is often pain across the lower arm and forearm, with some weakness in the intrinsic muscles of the hand, and a history of cigarette smoking.

Impingement of the sympathetic cervical ganglion leads to Horner's syndrome of the eye, with ptosis and constriction of the pupil.

Physical examination shows decreased breath sounds and pain in the axilla and Horner's syndrome. The most frequent pattern of distal neurologic involvement is decreased sensation in the 4th and 5th fingers, with weakness of the hand intrinsics. X-ray may show destruction of first or second ribs.

Treatment is directed at the tumor, and varies depending on cell type. Prognosis is poor.

This document was last modified on 06/14/2000 03:08:02 PM

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